Routing radio frequency (RF) signals from a source to an antenna array can involve many power dividers/couplers (e.g., “T” splitters) to properly feed antenna elements with a desired signal and/or signal strength. Two common approaches for such routing utilize printed circuit board type power dividers (e.g., microstrip or stripline dividers) or waveguide power dividers. Microstrip or stripline dividers are often used in applications that have wideband frequency operation and unbalanced power divisions. However, microstrip or stripline dividers can suffer from various signal losses (e.g., a high insertion loss) which can limit a maximum sensitivity of a communication apparatus that utilizes these types of dividers.
Waveguide dividers are desired due to their ability to be utilized with increased bandwidth in conjunction with low loss properties to facilitate increased system resolution in remote sensing applications and increased data transfer for wireless communications. However, wideband, unbalanced waveguide power dividers and combiners are not commonly utilized in radar systems, wireless communications, and other applications as there is little information available in literature regarding the design of such dividers and combiners. Accordingly, waveguide dividers are conventionally utilized used in narrowband applications (e.g., 5-10% fractional bandwidth) which utilize balanced power divisions. Typical unbalanced waveguide power dividers used in the aforementioned applications have a narrow operational bandwidth (e.g., less than 2.0% fractional bandwidth).
A number of challenges can be encountered during the design of wideband unbalanced waveguide power dividers, where such challenges can include:
a) Waveguides are not easily designed for broadband applications due to their dispersive nature.
b) There is minimal information available on how to formulate an unbalanced splitter design, and further, how to create a design that satisfies requirements regarding return loss, insertion loss, and/or phase balance.
c) Conventional coupler designs may be used to achieve desired power splits, but these designs have a much larger footprint (e.g., 2× or more) compared to a balanced waveguide divider, whereby the increase in size can be due to coupling through the broad wall of the waveguide, for example.
d) Conventional design methodologies to fabricate unique unbalanced waveguide power dividers with similar footprints to balanced dividers can be time intensive. For example, an impact on an electrical performance by various lengths/sizes is not well known, and accordingly, parametric sweeps of many different waveguide dimensions/features are required in electromagnetic modeling tools for each unique divider design.